PROJECTS Construction on the Hinze Dam upgrade is now progressing with a completion date scheduled for 2010. First concrete poured for Gold Coast dam Construction is progressing on the stage three upgrade of the Hinze Dam on the Nerang River near the Gold Coast. The project has a total cost of $400 million and is scheduled for completion in 2010. The project is being delivered by the Hinze Dam Alliance which comprises SEQ Water and non-owner partners Thiess, SKM and URS which is the structural engineer. The upgrade will raise the dam wall by 15m to 108.5m above sea level, increasing water supply from the dam to 225ML/d. After the upgrade, the dam will have a full storage capacity of 309,700ML and will be one of the highest central core earth and rock fi ll dams in Queensland. The 15m raising of the embankment includes raising the existing main embankment and saddle dam as well as extending the saddle dam across the right abutment area by approximately 800m. With the design completed, key operations such as quarry and aggregate production have been commissioned. The first foundation has been exposed and prepared, rockfi ll has been placed, the fi rst concrete was recently poured and construction of the cut-off walls has begun. In addition to the 3D computer modelling used in the design phase, a physical scale model was built to further develop the 20 Concrete in Australia Vol 34 No 4 spillway design. This model was used to demonstrate to the peer review panel and the Queensland dam safety regulator that the full range of fl oods could be safely passed through the spillway. A major challenge for the design team was dealing with the foundation conditions at the right abutment. The proposed foundation treatment developed by the URS team and sub- alliance partner Bauer Specialtiefbau includes the construction of a cut off wall to depths of up to 50m. Geotechnical investigations at the site were completed in April. Over 80 boreholes were drilled and over 200 testpits and trenches were dug. URS then completed a probabilistic seismic hazard study to confi rm the design earthquake loads for the raised towers and the results of this study have allowed a reduction in the scope of work required, delivering a saving to the project. To promote fi sh movement in the Nerang and Little Nerang Rivers that feed the reservoir, the alliance will construct a trap and haul fi sh transfer system near the downstream toe of the dam to allow fi sh to move upstream beyond the embankment. The design of this system has been undertaken with close consultation with the Queensland Department of Primary Industries and Fisheries. Source: URS